Tungsten steel centering drill bit

Tungsten steel centering drill bit:

”A high stability self centering drill bit drill tip, with two symmetrical chip discharge grooves on both sides. The tool of the drill tip is upward, and the central part of the drill tip protrudes upward along its centerline to form a central tip. The upper surface of the drill tip on both sides of the central tip is the outer back cutting surface; The top of the central tip is a linear transverse blade, and the two sides of the transverse blade extend outward and downward in sequence as two transverse blade surfaces, two inner rear blade surfaces, and two oblique rear blade surfaces. The two ends of the transverse blade form two transition surfaces with the two chip discharge grooves, and the two transition surfaces intersect with the two outer rear blade surfaces to form a straight blade and the arc blade extending outward from the straight edge to form two outer blades. One side edge of the two transition surfaces forms an oblique blade with the corresponding oblique rear blade surface, and one side edge of the two transition surfaces forms an oblique blade with the corresponding inner rear blade surface. The inner edge of the straight line is connected to two inner edges, two inclined edges, and two outer edges at both ends of the transverse edge. The inclined edge is formed by connecting the middle straight edge and the two curved edges at both ends, The large distance between the two inclined blades is 20% -23% of the large diameter of the drill tip; The height difference between the top of the central tip and the upper ends of the two outer blades is 0.5-0.8mm, the angle between the straight blades of the two outer blades is 145 ° -147 °, the angle between the straight blades of the two oblique blades is 2 ° -6 °, and the angle between the two inner blades is 138 ° -140 °.

Furthermore, the angle between the inclined back blade surface and the centerline of the drill tip is 2 ° -6 °, the length of the transverse blade is 1-3mm, the transverse blade is an arc-shaped blade with a radius of 0.5-1.5mm, and the transverse blade surface extends from bottom to top in a wedge shape.

The beneficial effects of this utility model are:

This utility model improves the positioning tool of the drill tip by setting a central tip and providing a transverse blade, an inner blade, an oblique blade, a transverse blade surface, an inner rear blade surface, and an oblique rear blade surface at the central tip. By appropriately controlling the height difference between the top of the central tip and the upper end of the outer blade, the radial swing of the drill bit can be prevented as much as possible while ensuring the strength of the central tip, achieving good positioning effect. Especially for drill bits with a length to diameter ratio of ≥ 6 times, it is possible to directly drill holes without pre drilling, which can efficiently and stably complete deep hole processing with high smoothness, high straightness, high verticality, and no ripples on the hole wall.

Illustration of the drawings

Figure 1 is a schematic diagram of the three-dimensional structure of the high stability self centering drill bit drill tip according to the present utility model;

Figure 2 is a schematic diagram of the front view structure of the high stability self centering drill bit drill tip according to the present utility model;

Figure 3 is a schematic diagram of the left side structure of the high stability self centering drill bit drill tip according to the present utility model;

Figure 4 is a schematic diagram of the top view structure of the high stability self centering drill bit drill tip according to the present utility model, and its corresponding front view angle is different from that of Figure 2;

Figure 5 is a schematic diagram of the structure of the high stability self centering drill bit tip installed on the drill rod according to the present utility model.

Specific implementation method

Further explanation of the present utility model will be provided in conjunction with the accompanying drawings

As shown in Figures 1-4, the high stability self centering drill bit drill tip 8 of the present utility model is symmetrically provided with two chip discharge grooves 7a and 7b on both sides. The tool of the drill tip 8 is upward, and the central part of the drill tip 8 protrudes upward along its centerline to form a central tip 7. The upper surface of the drill tip 8 is located on the outer surfaces of the two sides of the central tip 7, which are respectively the outer rear cutting surfaces 9a and 9b. The top of the central tip 7 is a linear transverse blade 2, and the two sides of the transverse blade 2 extend outward and downward in sequence as two transverse cutting surfaces 5a/5b, two inner rear cutting surfaces 11a/11b, and two inclined rear cutting surfaces 10a/10b. Two transition surfaces 6a and 6b are formed between the two ends of blade 2 and the two chip discharge grooves 7a and 7b, respectively. The two transition surfaces 6a and 6b intersect with the two outer rear blade surfaces 9a and 9b to form a straight blade and an arc blade extending from the outer edge of the straight blade to form two outer blades 1a and 1b, and the two transition surfaces 6a and 6b Two inclined blades 3a and 3b are formed between one side edge of the transverse blade 2 and the corresponding two inclined rear blade surfaces 10a and 10b, respectively. Two straight inner blades 4a and 4b are formed between one side edge of the two transition surfaces 6a and 6b and the corresponding two inner rear blade surfaces 11a and 11b, respectively. Two inner blades 4a/4b, two inclined blades 3a/3b, and two outer blades 1a/1b are connected to each other at the two ends of the transverse blade 2. The two inclined blades 3a and 3b are respectively connected by a straight edge in the middle and curved edges at both ends. The large distance d between the two inclined blades 3a and 3b is 20% -23% of the large diameter D of the drill tip 8; The height difference w between the top of the central tip 7 and the upper ends of the two outer blades 1a and 1b is 0.5-0.8mm. The angle 1 β between the straight blades of the two outer blades 1a and 1b is 145 ° -147 °, the angle 3 β between the straight blades of the two oblique blades 3a and 3b is 2 ° -6 °, and the angle between the two inner blades 4a and 4b is 138 ° -140 °. The length h of the transverse blade 2 is 1-3mm, and the transverse blade is an arc-shaped blade with an arc radius of 0.5-1.5mm. The two transverse blade surfaces 5a and 5b respectively extend from bottom to top to form a wedge shape. The angle 2 β between the extended straight lines of the two ends of the transverse blade 2 is 138 ° -140 °; Two transition surfaces 6a and 6b are formed by extending diagonally downwards in the direction of θ (38 ° -42 °) from the two endpoints H and K of the transverse blade 2 in an "L" - shaped cross-sectional curve with a circular arc R, and intersecting with the two cutting grooves 7a and 7b, respectively.

As shown in Figure 5, when applied, the drill tip 8 is set on the tool holder 20. The specific setting method is generally as follows: the bottom of the drill tip 8 is designed as a joint for quick assembly and disassembly to form a replaceable drill bit, which can achieve quick installation and disassembly between the drill tip 8 and the tool holder 20; Alternatively, the drill tip 8 and the tool holder 20 can be designed with other connection methods as needed. Installing drill tip 8 on tool holder 20 can achieve good self centering effect, especially when the aspect ratio of the hole is greater than 6 times. *There is no need to drill pre holes first. By directly drilling with this drill tip 8, good hole size accuracy, straightness, and smoothness can be obtained, and no ripples are generated.